Furnace



T. A. MARSH FURIIAOE Filed llarchgg, 1923 nn. y

L A I z L Patented Jan. 17, 1928.

.UNITED STATES PATENT oruflcni."if;v

THOMAS A. MARSH, OF CHICAGO, ILLINOIS, ASSIGNOR TO GREEN ENGINEERING COI- 4 PYANY, OF EAST CHICAGO, INDIANA, A CORPORATION F ILLINOIS.

FURNACE.

Application tiled March 29, 1923. Serial No. 628,444.

This invention relates to furnaces equipped with mechanical stokersin the form of progressive feed or traveling grates.

The invention has particular reference to water cooled conduits at the sides of the grate to prevent clinker adherence to the furnace Walls at the sides of the grate'.

Among the objects of my invention is to locate the water boxes at the ends of these In conduits outside of the furnace Sett-ing so ready and convenient access may be had to the boxes and conduits throught-he former, and also to remove the boxes and joints of the conduits therewith away from the de- In teriorating effect of the heat of the fue'l bed on the grate.

A further object of my invention is to extend the forward ends of these conduits outward from the grate and through the `side walls of thefurnace setting so that the reduced temperatures of sald conduits will have no cooling effect on the fuel bed at the ignition zone thereof.

The invention consists further in the matters hereinafter described and more particularly set forth in the following claims.

In the accompanying drawings- Y Fig. 1 is a. longitudinal vertical sectional view taken through a furnace embodying the features of my invention;

Figs. 2 and 3 are transverse vertical sectional views taken on lines 2 2-and 3 3, res spectively, of Fig. l;

Fig. 4 is a horizontal detail sectional view taken on line 4--4 of Fig. 1; and 4 Fig. 5 is a horizontal sectional view through one of the side walls of the setting and showing another form of my invention.

The furnace structure shown in Fig. 1 in- 4o cludes a mechanical stoker in the form of an endless chain grate 1, which extends through the front wall 2 of the furnace setting toward the bridge wall 3 thereof. The rear or discharge end of the grate 1 terminates short of said bridge wall 3 to pro vide a vertical passage for the ash discharged over the rear end of said grate.

Extendin along both sides of the upper lead 5 of sa1d ate 1 are pipes or conduits 4, 4 `arran ed 1n pairs at each side of said lead with t e pipes in each p air spaced above each other, as shown in Fig. 2. As there shown, said pipes 4 are supported by the adjacent side walls 6, 6, o the furnacesetting, and are so located that they are 1n direc* Contact with the fuel bed carried by said grate lead 5 throughout all of the length thereof except at the frontend of the grate. From this place on to the rear end of the grate the conduits or pipes 4, 4 constitute the contact surfaces between the fuel bed .on the grate and the side walls 6, 6 and, being water cooled, prevent the incandescent fuel adhering to the side walls 6, 6 to damage them and form clinkers at the sides of the grate to impede the movement of the fuel bed.

`In the arrangement shown, said conduits 4, 4 are Awater cooled, and this may be done by including them in the boiler circulation. For this purpose, I provide boxes 7, 8 at the ends of each set of conduits and connect these boxes by pipes .9, 10, and 11 with the front and rear headers 12, 12, respectively, of the boiler. Each set of pipes 10 and 11 are joined by an interposed box 13, arranged as in Fig; 1. The boxes7 and 8 are at the inlet and outlet ends, respectively, of their set of pipes or conduits 4, 4 and, as shown in Fig. 1, these boxes are located exterior of the front and rear walls 2 and 14, respectively, for accessibility. Each box as shown has a removable hand hole cover a so that the insides of the boxes and pipes may be reached for cleaning, and also for attaching the ends of said conduits to the boxes on installation of the parts. Each set of conduits 4, 4 are inclined upwardly from the rear box 7 to facilitate the flow of steam bubbles occurring therein. Said conduits are also shaped and located so as to extend along and parallel the hottest zone of the fuel bed.

At the front end of the grate 1, the conduits 4, 4 curve outward from said grate through the side walls 6, 6 and lead into the boxes 8, 8,'which are located outside of these walls, as shown in Fig. 4. This takes the yconduits 4, 4 away from the zone of ignition of the incoming fresh or green fuel fed into the furnace. from the hopper 15, and thus prevents said conduits, by reason of their 10o reduced temperature, having any cooling effeetv on this ignition zone where all heat possible must be retained to gain proper and complete ignition of the incoming fuel with particles already aire. Moreover, with the 10:5`

boxes 8, 8 exterior of said side walls 6, 6, said boxes are out of the combustion chamber of the furnace and thus do not interfere with any parts of the stoker nor with the movemen* of said gate. This also applies'to the 110 rear boxes 7, 7. With all of the water boxes located exterior of the combustion chamber, the joints between the conduits 4 and boxes are outside the zone of heat and are therefore not subjected to extreme temperature changes.

As shown in Fig. 1, the conduits 4, 4 extend beyond the rear or tail end of the grate 1 and on through the bridge 3, as well as the rear wall 14. These conduits extend under the water back pipes 16, 16al and the pipe 17. The latter are spaced above the upper lead 5 a distance sufficient so that said conduits 4, 4 may pass under said pipes without bend. The water back pipes 16, 16 are connected together at one side of the furnace by an elbow 18 (Fig. 2) and are included in the boiler circulation by pipes 19, 20 at their opposits ends, as indicated in Fig. 1. The pipe 17 is water cooled and aids to Support the weight of the bridge wall overhang 21. The conduits 4, 4 being curved outward at their forward ends, provides each conduit with a bend between its ends. This allows the conduits to expand and contract under temperature changes without objectionable deteriorating strains or effects on the boxes 7, 8 with which they are connected or the joints between the parts.

In furnace installations requiring the lowermost water back pipe 16 to be at such a short distance above the grate lead 5 that there is no space left for the side conduits to pass thereunder as in Fig. 1, I may employ the arrangement Shown in Fig. 5. As there illustrated,l the side conduits 22 have their front and rear end portions directed away from the upper grate lead 23 through the adjacent side wall 24 of the furnace setting and terminate in water boxes 25, 26, the same as the ones Previous1 described, and which may be included in t ie boiler circulation as in Fig. 1. This arrangement places both boxes 25, 26 at the side wall 24, with the rear box 25 forward of the water back pipe 16 and thus forward of the rear or tail end of the grate.

Both-boxes are exterior of said wall 24 and are thus accessible from outside the combustion chamber into which the grate extends. Moreover, the rear end portions of the side conduits 22 are bent outward before reaching the water back pipe 16, and the latter may thus be located near the grate lead 23 as the conduits 22 do not pass under said water back pipe. The sections of said conduits 22 between their outwardly' bent end portions serve as Contact surfaces with the fuel bed during the zone of clinker formation and not much trouble is likely to develop in taking said conduits away from the grate at the rear, as shown in Fig. 5. There are a number of these conduits 22 at both sides of the grate lead 23, the same as shown in Fig. 2, w ich would answer for a section throuffh Fig. 5 where the conduits 22 contact with t ye fuel bed.

The main boiler, including the headers 12, 12 and interposed water tubes, together with the side conduits 4, 4, water back pipes 16, 16, and the connections of these several members into a completed whole, and the arrangement of parts thereof constitute an invention of the applicant herein, and which invention is covered by certain of the claims hereof. The pipes or conduits 4, 16, 16, 9, 10, 11, and 20 comprise in each instance a drawn steel boiler tube, bent cold. The water boxes or headers 7, 8, 13, 25, and 26 are of cast steel.

While I have shown and described herein in detail a furnace structure embodying the features of my invention.` it is of course to be understood that the details of construction and arrangement of parts illustrated `may be variously changed and modified Without departing from the spirit and scope of my invention.

I claim as my invention:

1. In a furnace having side walls, the combination with a traveling grate therebetween, of iiuid cooled conduits at the side of the grate and extending substantiall the full length thereof with the conduits su stantially uniform in diameter and continuous and unbroken from end to end, said conduits having their forward portions continued tothe front of the furnace past the ignition zone of the fuel bed on the grate at the front end of the latter and being bent outward from the grate in advance of said zone so as to have no cooling effect thereon, the remaining portions of the conduits continuing from said zone to the rear end of the grate and arranged to be in direct Contact with the fuel bed for more than half the length of the grate.

2. The combination in a furnace, of a grate, boiler elements above said grate, conduits extendingalong the opposite sides of said grate and arranged to be in direct contact with the fuel bed thereon, water boxes at the ends of said conduits pipes connecting said boxes with said boiler elements for placing the side conduits in boiler circulation, each box at one end of the grate being connected with said boiler elements by said pipes which are arranged at angles to each other and having a water box between their adjacent ends for connecting them together, all of the boxes being exterior of the furnace for accessibility and having hand holes with removable covers s0 that the insides of the boxesand conduits may be reached for connecting and cleaning.

In witness that I claim the fore oing as my invention, I affix my signature t is 23rd day of March, A. D. 1923.

THOMAS A. MARSH.

lUlJ 

